1. Field of the Invention
The present invention relates to a manipulator for driving a turnable joint.
2. Description of the Related Art
An endoscope which is capable of monitoring inside a body and performing appropriate treatments using treatment instruments where necessary has been used widely in the medical field. The endoscope usually has a bending section, configured as having a plurality of joints being connected in a turnable manner, at a distal end side of its insertion section in order to be able to be easily inserted into a flexural body.
One type of an endoscope would be a hand-operated type in which the bending section is bend-driven through manual operation (where operating force is required). An electromotive bending type endoscope has also been put to practical use. In the electromotive bending type endoscope, that is, a type that has a manipulator, electrical driving means such as a motor is used in bend-driving the bending section for the purpose of further enhancing operability.
With respect to a treatment instrument as well, some instruments have achieved further enhanced operability by adopting a manipulator which is configured to drive the bending section having a plurality of joints by driving means such as a motor through an instructing operation on a proximal side.
As one example in the prior art, for instance, Japanese Patent Application Laid-Open Publication No. 10-315173 discloses a device having a secondary filter as being a modeled position control section as well as a position control model section where positional instruction is received; and malfunction detecting means configured as including the secondary filter, a comparator, an absolute value transforming section, and a subtractor, the malfunction detecting means functioning to compare an output signal from the position control model section with a position signal indicating an actual position of an electrical motor that drives a robot, and thus detect malfunction in the robot when a difference between the compared two signals becomes equal to or greater than a predetermined value.
With this device, when a difference between a signal from an input system and an output signal at a time when the electrical motor is driven in response to the input signal from the input system is equal to or greater than a predetermined value, it is determined that there is malfunction in the robot, whereby possible malfunction can be found in an early stage where further runaway of the robot can be stopped.